Excavation machines, for example hydraulic excavators, dragline excavators, wheel loaders, and front shovels operate according to well known cycles to excavate and load material onto a nearby haul vehicle. A typical cycle includes a dig segment, a swing-to-truck segment, a dump segment, and a swing-to-trench segment. During each of these segments, the excavation machine performs differently. For example, during a dig segment, high forces and high precision are required to push a tool into the material at an optimum attack angle, while during a swing-to-truck or swing-to-trench segment, high velocities and low precision are required. As such, the excavation machine is often controlled differently according to what segment of the cycle is currently being completed. In addition, the way that the machine is controlled during each segment can affect productivity of the machine, and the way in which productivity is measured and analyzed.
In order to facilitate productive control of an excavation machine and quality data gathering associated with performance tracking of the machine, it can be important to accurately detect and/or classify which segment of the excavation cycle is currently being performed (i.e., detect when one segment has started, which segment it is, and when it ends). In the past, an operator could manually note the segment and adjust control and/or data logging accordingly. However, as the machines become more complicated, it may be too interruptive for the operator to continue to perform this function. In addition, many of today's machines are remotely or autonomously controlled. Accordingly, a system for automatically recognizing and classifying the different segments of the excavation cycle is required.
One such system is disclosed in U.S. Pat. No. 6,114,993 (the '993 patent) issued to Henderson et al. on Sep. 5, 2000. The '993 patent discloses an excavator equipped with a positioning system. Based on inputs from the positioning system, loading and dumping operation's of the excavator's work cycle are determined. The loading and dumping operations may be detected by monitoring the angular velocity of the excavator's body. The angular velocity is determined by monitoring multiple position updates of the body as the body rotates. The angular velocity is then used to determine when and where the body has stopped, and the amount of time the body is stopped. If the body has stopped over an area that has not been mined, and is stopped for a predetermined amount of time, for example seven seconds or longer, the conclusion may be made that the excavator has loaded it's bucket. Similarly, if the body stopped over an area that has been mined, and is stopped for a predetermined amount of time, the conclusion may be made that the excavator has dumped its load. In this manner, the work cycle of the excavator may be segmented. In an alternative embodiment, the loading and dumping operations are determined using inputs from the positioning system, in conjunction with additional sensors such as a payload monitoring system.
Although the excavator of the '993 patent may utilize velocity and payload information to help segment a work cycle, it may be complicated and lack applicability. That is, the excavator requires knowledge about what has and hasn't yet been excavated, which can be difficult to attain and track. Without this information, it may not be possible to segment the work cycle. And, the excavator segments the work cycle only when the machine has stopped. It is not uncommon for an operator of the machine to never bring the machine to a complete stop during dumping. In these circumstances, the excavator of the '993 patent may be unable to fully segment the cycle.
The disclosed control system is directed to overcoming one or more of the problems set forth above.